This invention relates to mechanical clutches and more particularly to synchronized type mechanical clutches.
In prior art synchronizers, the spline teeth on the sleeve member and on the ratio or speed gear member include oblique surfaces which cooperate during engagement of the clutch to prevent inadvertent disengagement and to limit the longitudinal movement of the ratio gear relative to the sleeve member. The surfaces preventing inadvertent disengagement are designed to have a surface which angles relative to the longitudinal axis. The arctangent of the angle of inclination is generally equal to or greater than the coefficient of friction of the mating members. Thus, when a driving relationship is occurring between these surfaces, the frictional forces preventing longitudinal movement are greater than the component of the drive force seeking to separate the members.
The conventional synchronizer also has an oblique surface on the spline teeth which limits the longitudinal movement in the engage direction. The combination of these surfaces prevents relative longitudinal movement between the sleeve member and the ratio gear. During power transmission, however, the ratio gear is subjected to torque reversals and due to these torque reversals and the helix angle on the ratio gear, fore and aft movement of the ratio gear occurs. This fore and aft movement of the ratio gear is transmitted through the synchronizer sleeve to the manual shift control lever in the operator compartment of the vehicle.